Saturday's Welsh Premier League play-off semi-final between Carmarthen Town and Rhyl will be played at Port Talbot's GenQuip Stadium.
A pitch inspection was held at Carmarthen's Richmond Park on Friday lunchtime after heavy overnight rain.
Officials decided to make an early decision to switch venues to benefit travelling supporters.
The winners will face Bangor City or Newtown to play-off for a Europa League spot.
Carmarthen have been forced to switch a number of home matches to alternative venues this season because of problems with the Richmond Park pitch